Which of the following chemical structures can form hydrogen bonds with water? methane (ch4), molecular oxygen (o2), hydrogen sulfide. explain.

Molecular oxygen and Hydrogen fluoride.

Explanation:

Definition:

Hydrogen bonding:

It is a type of dipole-dipole attraction between the hydrogen atom and more electronegative atoms.

In hydrogen bonding mostly the highly electronegative atoms are fluorine, nitrogen and oxygen.

Explanation:

In given compound such as methane CH₄ the electronegativity of carbon is 2.55 while that of hydrogen is 2.2 so there is smaller electronegativity difference that's why it can not form hydrogen bond.

In case of molecular oxygen the electronegativite atom oxygen is present. It can form hydrogen bonds with water. its electronegativity is 3.44.

In case of hydrogen fluoride the electronegativity atom fluorine is present. It will form hydrogen bonds with water. Its electronegativity is 3.98. So it is more likely to take part in hydrogen bonding.

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.